1. Technical Field
Embodiments of the present invention relate to a sealing structure, a developing device, a cleaning device, a process unit, and an image forming apparatus.
2. Related Art
In image forming apparatuses, a developing device develops an electrostatic latent image formed on a photoconductive drum by electrostatically affixing electrically charged fine particle toner as developer thereto.
In such a developing device, the toner tends to leak from the developing device, contaminating the interior of the image forming apparatus, and causing defective image formation. This problem immediately becomes apparent upon replacement of the developing device.
In particular, in a developing device that uses a non-magnetic one-component developer, toner is prone to toner leakage around a developing roller. That is, as a grain size of the toner shrinks to meet increasing demand for better image quality, toner tends to drop from a thin layer of toner formed on the developing roller.
To prevent such toner leakage, a number of countermeasures have been proposed. For example, when an entrance seal is brought in sliding contact with a developing roller, ends of the entrance seal are prone to tensile deformation (i.e., curling) causing leakage of toner migrating along the transformed portion. To prevent such curling, the corners of the entrance seal are diagonally cut to form trapezoidal shapes to reduce the area of sliding contact with the developing roller and thus minimize the curling.
Alternatively, multiple inclined toner guiding grooves are formed in the seal to recapture toner about to leak from both ends of a developing roller and return it to a center thereof in its axial direction.
To prevent such toner leakage, both ends of an entrance seal and a pair of edge seals may be separated in a circumferential direction so as not to overlap. Hence, since the entrance seal and the edge seals do not overlap in the circumferential direction, the overlapping steps are accordingly not formed, respectively.